Just another update

Task/Hailstone-sequence/Pascal/hailstone-sequence.pascal

@@ -0,0 +1,94 @@
+program ShowHailstoneSequence;
+{$IFDEF FPC}
+  {$MODE delphi} //or objfpc
+{$Else}
+  {$Apptype Console} // for delphi
+{$ENDIF}
+
+uses
+  SysUtils;// format
+type
+  tIntArr = record
+               iaAktPos : integer;
+               iaMaxPos : integer;
+               iaArr    : array of integer;
+            end;
+
+procedure GetHailstoneSequence(aStartingNumber: Integer;var aHailstoneList: tIntArr);
+var
+  n: UInt64;
+begin
+  with aHailstoneList do
+  begin
+    iaAktPos := 0;
+    iaArr[iaAktPos] := aStartingNumber;
+    n := aStartingNumber;
+    while n <> 1 do
+    begin
+      if Odd(n) then
+        n := (3 * n) + 1
+      else
+        n := n div 2;
+      inc(iaAktPos);
+      IF iaAktPos>iaMaxPos then
+      Begin
+        iaMaxPos := round(iaMaxPos*1.62)+2;
+        setlength(iaArr,iaMaxPos+1);
+      end;
+      iaArr[iaAktPos] := n;
+    end;
+  end;
+end;
+
+var
+  i,Limit: Integer;
+  lList: tIntArr;
+  lMaxSequence: Integer;
+  lMaxLength: Integer;
+begin
+  try
+    with lList do
+    begin
+      setlength(iaArr,0+1);
+      iaMaxPos := 0;
+      iaAktPos := 0;
+    end;
+
+    GetHailstoneSequence(27, lList);
+    with lList do
+    begin
+      i := iaAktPos+1;
+      Writeln(Format('27: %d elements', [i]));
+      Writeln(Format('[%d,%d,%d,%d ... %d,%d,%d,%d]',
+        [iaArr[0], iaArr[1], iaArr[2], iaArr[3],
+      iaArr[i - 4], iaArr[i - 3], iaArr[i - 2], iaArr[i - 1]]));
+      Writeln;
+
+      lMaxSequence := 0;
+      lMaxLength := 0;
+      limit := 10;
+      for i := 1 to 10000000 do
+      begin
+        GetHailstoneSequence(i, lList);
+        if iaAktPos >= lMaxLength then
+        begin
+          IF i> limit then
+          begin
+            Writeln(Format('Longest sequence under %8d : %7d with %3d elements',
+                           [limit,lMaxSequence, lMaxLength]));
+            limit := limit*10;
+          end;
+          lMaxSequence := i;
+          lMaxLength := iaAktPos+1;
+        end;
+      end;
+      Writeln(Format('Longest sequence under %8d : %7d with %3d elements',
+                     [limit,lMaxSequence, lMaxLength]));
+
+    end;
+  finally
+    setlength(lList.iaArr,0);
+  end;
+  writeln('game over, wait for >ENTER< ');
+  Readln;
+end.